Power absorption and generation at the ankle is critical to gait efficiency, joint health, and safety. For amputees, it's also an important factor n residual limb health. Recently, research and commercial efforts have resulted in powered foot-ankle systems, which provide powered- plantarflexion electromechanically, reduce metabolic costs of walking, and show reductions in pathological loading of the contralateral limb. However, these devices are complex, expensive, heavy, and physically large - all factors which limit widespread adoption. The objective of the energy-harvesting mesofluidic impulse prosthesis (e-MIP) is to create an inexpensive, lightweight foot-ankle system which doesn't require a net energy input for powered plantarflexion and swing-phase dorsiflexion. The energy density and bandwidth of high pressure, meso-scale hydraulics enables an ankle that can seamlessly harvest the energy normally dissipated in gait; store it in fluid-accumulators; and reapply it in controlled, well timed power impulses. The benefits of powered systems are therefore realized in an anthropometric size and weight, with a system complexity that is clinically viable.